The correct answer is: c) Decentralized chiefdoms.
Mizo society during this period was primarily organized into decentralized chiefdoms. This means that there was no single ruler or government, but rather a number of different chiefs who ruled over different parts of the land. These chiefs were often related to each other, and they would often work together to make decisions that affected the whole community.
There are a number of reasons why Mizo society was organized in this way. One reason is that the land that the Mizos lived in was very mountainous, which made it difficult to travel and communicate. This made it difficult to have a centralized government, as it would have been difficult for the government to control all of the different parts of the land.
Another reason why Mizo society was organized in this way is that the Mizos were a very independent people. They did not like to be ruled by others, and they preferred to make their own decisions. This made it difficult to have a centralized government, as the people would not have been willing to follow the orders of a government that they did not believe in.
Finally, Mizo society was organized in this way because it was the most effective way to deal with the challenges that the Mizos faced. The Mizos were often attacked by other groups, and they needed to be able to defend themselves. A decentralized chiefdom was the best way to do this, as it allowed the Mizos to work together to defend themselves against their enemies.
The other options are incorrect because they do not accurately reflect the way that Mizo society was organized during this period. Option a) is incorrect because there was no single centralized kingdom during this period. Option b) is incorrect because there were no large city-states during this period. Option d) is incorrect because Mizo society was not organized into egalitarian communes during this period.